Glass, glass ceramic, and laminated ceramic electronic component

ABSTRACT

A glass that contains Si, B, Al, and Zn. The glass has SiO 2  at a content of 15% by weight to 65% by weight, B 2 O 3  at a content of 11% by weight to 30% by weight, Al 2 O 3 , and ZnO, wherein a weight ratio of the SiO 2  to the B 2 O 3  (SiO 2 /B 2 O 3 ) is 1.21 or higher, and a weight ratio of the Al 2 O 3  to the ZnO (Al 2 O 3 /ZnO) is 0.75 to 1.64, and wherein an alkaline-earth metal is excluded as a material contained in the glass.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of International application No. PCT/JP2021/022433, filed Jun. 14, 2021, which claims priority to Japanese Patent Application No. 2020-104657, filed Jun. 17, 2020, Japanese Patent Application No. 2020-104658, filed Jun. 17, 2020, Japanese Patent Application No. 2020-192650, filed Nov. 19, 2020, and Japanese Patent Application No. 2020-192651, filed Nov. 19, 2020, the entire contents of each of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to glass, glass ceramics, and multilayer ceramic electronic components.

BACKGROUND OF THE INVENTION

Known ceramic materials for ceramic multilayer circuit boards include low temperature fireable glass ceramic materials.

For example, Patent Literature 1 discloses a glass composition for low temperature fired substrates, having a basic composition of RO-Al₂O₃—B₂O₃—SiO₂, wherein RO is one or two or more of MgO, CaO, SrO, BaO, and ZnO, RO and Al₂O₃ are each within a range of 1 to 25 mol %, and the mol % ratio SiO₂/B₂O₃ is 1.3 or lower; and a glass ceramic containing the glass composition for low temperature fired substrates containing an aggregate.

-   Patent Literature 1: JP 2004-26529 A

SUMMARY OF THE INVENTION

The glass ceramic disclosed in Patent Literature 1 can achieve an excellent dielectric loss of 20×10⁻⁴ or lower at 3 GHz.

However, the glass composition for low temperature fired substrates disclosed in Patent Literature 1 has a SiO₂/B₂O₃ mol % ratio of 1.3 or lower, i.e., a high boron (B) content. Such a boron-rich glass composition causes an unstable boron content. Specifically, boron may be dissolved into a solvent during mixing grinding or may be evaporated during firing. If the boron content is reduced as a result of dissolution or evaporation, the viscosity of the glass may be low during firing, causing insufficient sintering. Glass from which boron is released due to dissolution or evaporation is chemically unstable and have poor resistance to moisture and to plating solutions, potentially causing poor quality.

The above situation thus causes a demand for a glass material having a low boron content and a low dielectric loss.

The present invention is made to solve the above issues and aims to provide a glass having a low boron content and a low dielectric loss.

The glass of the present invention contains Si, B, Al, and Zn. Specifically, the glass has SiO₂ at a content of 15% by weight to 65% by weight, B₂O₃ at a content of 11% by weight to 30% by weight, Al₂O₃, and ZnO, wherein a weight ratio of the SiO₂ to the B₂O₃ (SiO₂/B₂O₃) is 1.21 or higher, and a weight ratio of the Al₂O₃ to the ZnO (Al₂O₃/ZnO) is 0.75 to 1.64, and wherein an alkaline-earth metal is excluded as a material contained in the glass.

The glass ceramic of the present invention contains 45% by weight to 100% by weight of the glass of the present invention.

The multilayer ceramic electronic component of the present invention includes multiple glass ceramic layers each of which is a sintered article of the glass ceramic of the present invention.

The present invention can provide a glass having a low boron content, a low permittivity, and a low dielectric loss, a glass ceramic containing the glass, and a multilayer ceramic electronic component including multiple glass ceramic layers each of which is a sintered article of the glass ceramic.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-sectional view of an example of the multilayer ceramic electronic component of the present invention.

FIG. 2 is a schematic cross-sectional view of a multilayer green sheet (non-fired) produced in the course of production of the multilayer ceramic electronic component illustrated in FIG. 1 .

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The glass, glass ceramic, and multilayer ceramic electronic component of the present invention are described hereinbelow. The present invention is not limited to the following structures and may be suitably modified without departing from the gist of the present invention. Combinations of two or more preferred structures described in the following are also within the scope of the present invention.

<Glass>

The glass of the present invention contains Si, B, Al, and Zn, and has a SiO₂ content of 15% by weight to 65% by weight, a B₂O₃ content of 11% by weight to 30% by weight, a weight ratio of SiO₂ to B₂O₃ (SiO₂/B₂O₃) of 1.21 or higher, and a weight ratio of Al₂O₃ to ZnO (Al₂O₃/ZnO) of 0.75 to 1.64, and wherein an alkaline-earth metal is excluded as a material contained in the glass.

B₂O₃ in the glass contributes to a low viscosity of the glass and thus allows a sintered article of the glass ceramic to be dense.

The glass of the present invention has a B₂O₃ content of 11% by weight to 30% by weight and a weight ratio of SiO₂ to B₂O₃ (SiO₂/B₂O₃) of 1.21 or higher, which means that the proportion of B₂O₃ in the whole glass is small. This therefore less easily causes release of boron from the glass due to dissolution or evaporation and eventually less easily causes issues such as insufficient sintering and poor resistance to plating solutions. The glass of the present invention preferably has a B₂O₃ content of 15% by weight to 30% by weight.

The glass of the present invention has a SiO₂ content of 15% by weight to 65% by weight, preferably 20% by weight to 60% by weight.

A SiO₂ content of 15% by weight to 65% by weight contributes to a low permittivity of a sintered glass ceramic containing the glass of the present invention. This resultantly leads to, for example, reduction in the stray capacity due to electrical signals with higher frequencies.

A SiO₂ content of higher than 65% by weight causes issues such as difficulty in sintering at 1000° C. or lower and less precipitation of ZnAl₂O₄ crystals. In contrast, since the SiO₂ content is 65% by weight or less in the present invention, these issues do not occur.

A SiO₂ content of lower than 15% by weight causes too low a viscosity to achieve vitrification.

The weight ratio of SiO₂ to B₂O₃ (SiO₂/B₂O₃) is 1.21 or higher. A weight ratio of SiO₂ to B₂O₃ (SiO₂/B₂O₃) within this range less easily causes release of boron from the glass due to dissolution or evaporation.

The weight ratio of SiO₂ to B₂O₃ (SiO₂/B₂O₃) is preferably 5.91 or lower, more preferably 4 or lower.

A weight ratio of SiO₂ to B₂O₃ (SiO₂/B₂O₃) of lower than 1.21 means too much B₂O₃ relative to SiO₂, which easily causes dissolution or evaporation of boron.

Al₂O₃ in the glass contributes to improved chemical stability of the glass.

Zn in the glass forms ZnAl₂O₄ together with Al.

The glass of the present invention contains Al and Zn. Al and Zn contained in the glass precipitate in the form of ZnAl₂O₄ crystals, which contribute to a low loss, in the glass.

A weight ratio of Al₂O₃ to ZnO (Al₂O₃/ZnO) of 0.75 to 1.64 or lower allows the glass to have a ZnAl₂O₄ content within a preferred range.

A weight ratio of Al₂O₃ to ZnO (Al₂O₃/ZnO) of lower than 0.75 means too much ZnO and causes a low Q value, which is the reciprocal of the dielectric loss. In contrast, a weight ratio of Al₂O₃ to ZnO (Al₂O₃/ZnO) of higher than 1.64 means too much Al₂O₃ and causes a high viscosity of the glass, resulting in a failure in providing a dense sintered article.

The weight ratio of Al₂O₃ to ZnO (Al₂O₃/ZnO) may be 0.75 or higher and 1.63 or lower.

The glass of the present invention may further contain a sub-component.

The glass of the present invention may contain Li as a sub-component. The Li₂O content is preferably 0.05% by weight to 1% by weight.

Li₂O in the glass contributes to a low viscosity of the glass. Li₂O contained in the glass leads to improved sinterability.

A predetermined amount of Li₂O can lead to good sinterability and a low dielectric loss even when a glass ceramic containing the glass of the present invention contains 40% by weight or more of an aggregate.

The glass of the present invention may further contain a different sub-component in addition to the Li-containing sub-component.

The different sub-component preferably includes at least one metal selected from the group consisting of an alkali metal, and a different metal from that of a main component of the glass.

The alkali metal preferably includes at least one selected from the group consisting of Na and K.

The different metal preferably includes at least one selected from the group consisting of Ti, Zr, and Sn.

The sum of the amounts of the sub-components is preferably 0.05% by weight to 5% by weight, more preferably 0.1% by weight to 5% by weight of the weight of the whole glass. The sum of the amounts of the sub-components means the sum of the amount of the Li-containing sub-component and the amount of the different component. A predetermined amount of the sub-components can promote crystallization of the glass and contribute to a low dielectric loss.

<Glass Ceramic>

The glass ceramic of the present invention contains 45% by weight to 100% by weight of the glass of the present invention.

The glass ceramic of the present invention contains 45% by weight or more of the glass of the present invention and can therefore achieve a low permittivity and a low dielectric loss. Also, the glass ceramic of the present invention contains 45% by weight or more of the glass of the present invention and therefore less suffers issues such as insufficient sintering due to dissolution or evaporation of boron and poor resistance to plating solutions.

The glass ceramic of the present invention preferably contains 50% by weight to 100% by weight of the glass of the present invention.

The glass ceramic of the present invention is a low temperature co-fired ceramic (LTCC) material. The “low temperature co-fired ceramic material” herein means a glass ceramic material sinterable at a firing temperature of 1000° C. or lower.

The glass ceramic of the present invention may further contain an aggregate.

The aggregate may include at least one compound selected from the group consisting of SiO₂, TiO₂, ZnO₂, ZrO₂, Al₂O₃, and BaO.

In the case where the glass ceramic of the present invention contains an aggregate, the glass content is preferably 45% by weight to less than 100% by weight, more preferably 50% by weight to less than 100% by weight.

SiO₂ as an aggregate is preferably in the form of quartz and/or amorphous silica.

Quartz can contribute to a high coefficient of thermal expansion of a sintered glass ceramic. The coefficient of thermal expansion of the glass is about 6 ppm/K, while the coefficient of thermal expansion of the quartz is about 15 ppm/K. Thus, the presence of quartz in the glass ceramic may lead to a high coefficient of thermal expansion after sintering. This may generate a compression stress in the course of cooling after sintering, resulting in a high mechanical strength (e.g., flexural strength), as well as high reliability in mounting the product on a mounting board (e.g., a resin board).

Al₂O₃ and ZrO₂ as aggregates can prevent precipitation of cristobalite crystals during sintering of the glass ceramic. The cristobalite crystal is a type of SiO₂ crystal and exhibits a phase transition at about 280° C. Thus, precipitation of cristobalite crystals in the course of sintering of the glass ceramic may greatly change the volume in a high-temperature environment, causing poor reliability. From this viewpoint, the glass ceramic is preferably free from cristobalite crystals. The expression “free from cristobalite crystals” herein means that the amount of cristobalite crystals is not higher than the detection limit. The presence or absence of precipitation of cristobalite crystals is confirmed by crystal structure analysis such as X-ray diffraction (XRD).

Al₂O₃ and ZrO₂ as aggregates can also contribute to a low dielectric loss, high coefficient of thermal expansion, and high mechanical strength of a sintered glass ceramic.

TiO₂ as an aggregate has a high temperature coefficient of relative permittivity (TCC) with the minus sign and thus enables control of TCC of the glass ceramic.

ZnO as an aggregate can lead to improved sinterability and can compensate for volatile ZnO components in the glass.

BaO as an aggregate can exhibit an effect as a sintering aid.

BaO may be added in the form of a compound containing Ba and O, such as BaCO₃, BaZrO₃, or Si—B—Ba—O glass.

For the glass ceramic, the glass and the aggregate can be distinguished by analyzing the electron diffraction pattern using a transmission electron microscope (TEM).

The amount of the aggregate can be determined by dividing the weight of the elements defining the aggregate excluding oxygen in the form of oxide by the weight of the whole glass ceramic. Accordingly, when BaZrO₃ is contained as an aggregate, both BaO and ZrO₂ are contained as aggregates.

<Multilayer Ceramic Electronic Component>

The multilayer ceramic electronic component of the present invention includes multiple glass ceramic layers each of which is a sintered article of the glass ceramic of the present invention.

Examples of the multilayer ceramic electronic component of the present invention include a laminate including multiple glass ceramic layers each of which is a sintered article of the glass ceramic of the present invention, and an electronic component including a multilayer ceramic substrate that includes the laminate and a chip component mounted on the multilayer ceramic substrate.

The multilayer ceramic electronic component of the present invention includes multiple glass ceramic layers each of which is a sintered article of the glass ceramic of the present invention, and thus has a low permittivity and a low dielectric loss.

The laminate including multiple glass ceramic layers each of which is a sintered article of the glass ceramic of the present invention may be used for a ceramic multilayer substrate for communications and a multilayer dielectric filter, for example.

Each glass ceramic layer preferably has a coefficient of thermal expansion of 6 ppm/K or higher.

Each glass ceramic layer preferably has a relative permittivity of 5.5 or lower.

Each glass ceramic layer preferably has a Q value of 1000 or higher.

Each glass ceramic layer preferably has a temperature characteristic of relative permittivity (TCC) of −60 ppm/K or higher and +60 ppm/K or lower.

FIG. 1 is a schematic cross-sectional view of an example of the multilayer ceramic electronic component of the present invention. As illustrated in FIG. 1 , an electronic component 2 includes a laminate 1 including a stack of multiple (five in FIG. 1 ) glass ceramic layers 3 and chip components 13 and 14 mounted on the laminate 1. The laminate 1 is also a multilayer ceramic substrate.

Each of the glass ceramic layers 3 is a sintered article of the glass ceramic of the present invention. Thus, the laminate 1 including the stack of multiple glass ceramic layers 3 and the electronic component 2 including a multilayer ceramic substrate that includes the laminate 1 and the chip components 13 and 14 mounted on the multilayer ceramic substrate (laminate 1) are each the multilayer ceramic electronic component of the present invention. The compositions of the multiple glass ceramic layers 3 may be the same as or different from each other, and are preferably the same as each other.

The laminate 1 may further include a conductive layer. For example, the conductive layer defines a passive element such as a capacitor or an inductor or defines a connection line that provides an electrical connection between elements. Examples of the conductive layer include conductive layers 9, 10, and 11 as well as via hole conductive layers 12, as illustrated in FIG. 1 .

The conductive layers 9, 10, and 11 as well as the via hole conductive layers 12 preferably contain Ag or Cu as a main component. Use of such a low-resistance metal can prevent occurrence of signal propagation delay due to electrical signals with higher frequencies. The constituent material of each glass ceramic layer 3 used is the glass ceramic of the present invention, i.e., a low temperature co-fired ceramic material, and thus can be co-fired with Ag or Cu.

The conductive layers 9 are provided inside the laminate 1. Specifically, the conductive layers 9 are provided at interfaces of glass ceramic layers 3.

The conductive layers 10 are provided on one main surface of the laminate 1.

The conductive layers 11 are provided on the other main surface of the laminate 1.

The via hole conductive layers 12 are each provided to penetrate a glass ceramic layer 3 and play a role of electrically connecting conductive layers 9 of different levels, electrically connecting conductive layers 9 and 10, or electrically connecting conductive layers 9 and 11.

The laminate 1 may be produced as follows, for example.

(A) Preparation of Glass

SiO₂, B₂O₃, Al₂O₃, and ZnO as well as a sub-component to be optionally added are mixed such that the SiO₂ content is 15% by weight to 65% by weight, the B₂O₃ content is 11% by weight to 30% by weight, the weight ratio of SiO₂ to B₂O₃ (SiO₂/B₂O₃) is 1.21 or higher, and the weight ratio of Al₂O₃ to ZnO (Al₂O₃/ZnO) is 0.75 to 1.64. Thereby, the glass of the present invention is prepared. The SiO₂ content in the glass is preferably 20% by weight to 60% by weight. The B₂O₃ content in the glass is preferably 15% by weight to 30% by weight.

(B) Preparation of Glass Ceramic

The glass of the present invention is optionally mixed with an aggregate as appropriate whereby the glass ceramic of the present invention is prepared.

The glass ceramic of the present invention is prepared such that it contains 45% by weight to 100% by weight of the glass of the present invention.

(C) Production of Green Sheet

The glass ceramic of the present invention is mixed with components such as a binder and a plasticizer, whereby ceramic slurry is prepared. The ceramic slurry is applied in a pattern to a base film (e.g., a polyethylene terephthalate (PET) film) and dried, whereby a green sheet is produced.

(D) Production of Multilayer Green Sheet

The green sheets are stacked, whereby a multilayer green sheet (non-fired) is produced. FIG. 2 is a schematic cross-sectional view of a multilayer green sheet (non-fired) produced in the course of production of the multilayer ceramic electronic component illustrated in FIG. 1 . As illustrated in FIG. 2 , a multilayer green sheet 21 includes a stack of multiple (five in FIG. 2 ) green sheets 22. The green sheets 22 are to be the glass ceramic layers 3 after firing. The multilayer green sheet 21 may be provided with conductive layers including the conductive layers 9, 10, and 11 as well as the via hole conductive layers 12. The conductive layers may be formed by a technique such as screen printing or photolithography using a conductive paste containing Ag or Cu.

(E) Firing of Multilayer Green Sheet

The multilayer green sheet 21 is fired. As a result, the multilayer ceramic substrate 1 as illustrated in FIG. 1 is obtained.

The firing temperature for the multilayer green sheet 21 may be any temperature at which the glass ceramic of the present invention defining the green sheets 22 can be sintered, and may be 1000° C. or lower.

The firing atmosphere for the multilayer green sheet 21 may be any atmosphere, and is preferably the air atmosphere in the case where an oxidation-resistive material such as Ag is used for the conductive layers 9, 10, and 11 as well as the via hole conductive layers 12, or preferably an oxygen-poor atmosphere such as a nitrogen atmosphere in the case where an easily oxidative material such as Cu is used therefor. The firing atmosphere for the multilayer green sheet 21 may be a reduced atmosphere.

The multilayer green sheet 21 may be fired while sandwiched between restraining green sheets. The restraining green sheets each contain as a main component an inorganic material (e.g., Al₂O₃) that is substantially unsinterable at the sintering temperature for the glass ceramic of the present invention defining the green sheets 22. Thus, the restraining green sheets do not shrink during firing of the multilayer green sheet 21 but act to reduce shrinkage of the multilayer green sheet 21 in the main surface direction. They can resultantly lead to improved dimensional accuracy of the resulting laminate 1 (particularly the conductive layers 9, 10, and 11 as well as the via hole conductive layers 12).

The laminate 1 may be provided with the chip components 13 and 14 each electrically connected with a conductive layer 10. Thereby, the electronic component 2 including the laminate 1 is fabricated.

Examples of the chip components 13 and 14 include an LC filter, a capacitor, and an inductor.

The electronic component 2 may be mounted on a board (e.g., motherboard) so as to be electrically connected therewith via the conductive layers 11.

Examples

The following provides examples that more specifically disclose the glass, glass ceramic, and multilayer ceramic electronic component of the present invention. The present invention is not limited to these examples.

(A) Preparation of Glass

Glasses G1 to G41 (each in the form of powder) having the respective compositions shown in Table 1 were prepared by the following method. First, glass material powders were mixed and put into a Pt-Rh crucible, and then melted at 1650° C. for six hours or longer in the air atmosphere. The resulting melt was rapidly cooled, whereby cullet was produced. The cullet was coarsely pulverized and put into a container together with an organic solvent and PSZ balls (diameter: 5 mm). The contents were then mixed using a ball mill. The pulverization duration in the mixing with the ball mill was adjusted so that a glass powder having a central particle size of 1.5 μm was obtained. The “central particle size” herein means the central particle size D₅₀ measured by laser diffraction-scattering analysis.

TABLE 1 Glass SiO₂ B₂O₃ Al₂O₃ ZnO TiO₂ ZrO₂ SnO₂ SrO CaO BaO Li₂O SiO₂/B₂O₃ Al₂O₃/ZnO No. [wt %] [wt %] [wt %] [wt %] [wt %] [wt %] [wt %] [wt %] [wt %] [wt %] [wt %] weight ratio weight ratio G1 60.0 30.0 5.2 4.8 — — — — — — — 2.00 1.08 G2 59.4 18.8 10.9 10.9 — — — — — — — 3.16 1.00 G3 60.0 15.0 12.5 12.5 — — — — — — — 4.00 1.00 G4 55.0 20.0 12.5 12.5 — — — — — — — 2.75 1.00 G5 50.0 30.0 10.3 9.7 — — — — — — — 1.67 1.06 G6 50.0 15.0 17.5 17.5 — — — — — — — 3.33 1.00 G7 42.0 29.0 15.0 14.0 — — — — — — — 1.45 1.07 G8 40.0 20.0 20.6 19.4 — — — — — — — 2.00 1.06 G9 40.0 15.0 22.5 22.5 — — — — — — — 2.67 1.00 G10 29.0 24.0 24.2 22.8 — — — — — — — 1.21 1.06 G11 30.0 20.0 25.8 24.2 — — — — — — — 1.50 1.07 G12 30.0 15.0 28.4 26.6 — — — — — — — 2.00 1.07 G13 20.0 15.0 33.6 31.4 — — — — — — — 1.33 1.07 G14 42.9 28.6 14.4 13.6 0.5 — — — — — — 1.50 1.06 G15 41.0 27.3 13.8 13.0 5.0 — — — — — — 1.50 1.06 G16 41.6 28.6 14.9 13.9 — 1.0 — — — — — 1.45 1.07 G17 39.9 27.4 14.3 13.4 — 5.0 — — — — — 1.46 1.07 G18 41.6 28.6 14.9 13.9 — — 1.0 — — — — 1.45 1.07 G19 39.9 27.4 14.3 13.4 — — 5.0 — — — — 1.46 1.07 G20 43.2 19.2 16.8 16.8 — 1.0 — 3.0 — — — 2.25 1.00 G21 42.8 19.0 16.6 16.6 — — — 5.0 — — — 2.25 1.00 G22 42.3 18.8 16.5 16.5 — 1.0 — — 5.0 — — 2.25 1.00 G23 42.6 19.0 16.7 16.7 — — — — — 5.0 — 2.24 1.00 G24 49.1 24.6 11.3 15.0 — — — — — — — 2.00 0.75 G25 42.9 24.1 20.5 12.5 — — — — — — — 1.78 1.64 G26 45.0 35.0 10.3 9.7 — — — — — — — 1.29 1.06 G27 30.0 10.0 30.9 29.1 — — — — — — — 3.00 1.06 G28 42.9 24.1 13.5 19.5 — — — — — — — 1.78 0.69 G29 42.9 24.1 21.8 11.2 — — — — — — — 1.78 1.95 G30 65.0 20.0 7.8 7.2 — — — — — — — 3.25 1.08 G31 15.0 20.0 33.6 31.4 — — — — — — — 0.75 1.07 G32 30.0 30.0 20.6 19.4 — — — — — — — 1.00 1.06 G33 45.0 15.0 20.0 20.0 — — — — — — — 3.00 1.00 G34 45.0 14.95 20.0 20.0 — — — — — —  0.05 3.01 1.00 G35 45.0 14.0 20.0 20.0 — — — — — — 1.0 3.21 1.00 G36 45.0 12.0 20.0 20.0 — — — — — — 3.0 3.75 1.00 G37 65.0 30.0 2.5 2.5 — — — — — — — 2.17 1.00 G38 60.0 11.0 14.5 14.5 — — — — — — — 5.45 1.00 G39 40.0 11.0 24.5 24.5 — — — — — — — 3.64 1.00 G40 15.0 12.0 36.5 36.5 — — — — — — — 1.25 1.00 G41 75.0 15.0 5.0 5.0 — — — — — — — 5.00 1.00

The glasses G26 to G29, G31, G32, and G41 each are not the glass of the present invention.

The glass G26 has a B₂O₃ content of higher than 30% by weight.

The glass G27 has a B₂O₃ content of lower than 11% by weight.

The glass G28 has a weight ratio of Al₂O₃ to ZnO (Al₂O₃/ZnO) of lower than 0.75.

The glass G29 has a weight ratio of Al₂O₃ to ZnO (Al₂O₃/ZnO) of higher than 1.64.

The glass G31 has a SiO₂ content within a range of 15% by weight to 65% by weight and a B₂O₃ content of 11% by weight to 30% by weight, but has a weight ratio of SiO₂ to B₂O₃ (SiO₂/B₂O₃) of lower than 1.21.

The glass G32 has a SiO₂ content within a range of 15% by weight to 65% by weight and a B₂O₃ content of 11% by weight to 30% by weight, but has a weight ratio of SiO₂ to B₂O₃ (SiO₂/B₂O₃) of lower than 1.21.

The glass G41 has a SiO₂ content of higher than 65% by weight.

(B) Preparation of Glass Ceramic

Next, based on each composition shown in Table 2, the glass of the present invention optionally combined with aggregates was put into ethanol and mixed using a ball mill. Thereby, a glass ceramic was prepared. SiO₂ among the aggregates is quartz.

(C) Production of Green Sheet

One of the glass ceramics, a binder solution of polyvinyl butyral dissolved in ethanol, and a dioctyl phthalate (DOP) solution serving as a plasticizer were mixed, whereby ceramic slurry was prepared. The ceramic slurry was then applied in a pattern to a polyethylene terephthalate film using a doctor blade and dried at 40° C. Thereby, one of 25-μm-thick green sheets S1 to S33 and S35 to S47 was produced.

For the glass G31, the ceramic slurry was gelated and thus not subjected to the steps after production of green sheet.

(D) Production of Multilayer Green Sheet

Each of the green sheets S1 to S33 and S35 to S47 was cut to provide 78 mm×58 mm rectangles and 30 pieces thereof were stacked. The stack was put into a mold and compressed using a press, and then cut off at its side portions so as to have a 50-mm-square dimensions in a plan view. Thereby, respective multilayer green sheets were produced.

(E) Firing of Multilayer Green Sheet

The multilayer green sheets were fired at 980° C. for 60 minutes in a reduced atmosphere. The resulting fired articles were laminates L1 to L33 and L35 to L47 each including multiple glass ceramic layers each of which is a sintered article of the glass ceramic.

<Measurement of Relative Permittivity and Dielectric Loss>

For each of the resulting laminates L1 to L33 and L35 to L47, the thickness was measured and the relative permittivity and dielectric loss under 6 GHz conditions were measured by the perturbation method. The reciprocal of the measured dielectric loss was taken as the Q value. The results are shown in Table 2.

A relative permittivity of 5.5 or lower was evaluated as good. A Q value of 1000 or higher was evaluated as good. As stated in the Note of Example 2, the laminates L6, L29, L30, L32, L35, and L47 were insufficiently sintered.

The measurement devices and the measurement conditions were as follows.

Network analyzer: 8757D available from Keysight Technologies

Signal generator: 83751 synthesized sweeper available from Keysight Technologies

Resonator: self-made jig (resonance frequency: 6 GHz)

Before the measurement, the network analyzer and the signal generator were connected and the cable loss was measured. The resonator was calibrated using a reference substrate (quartz, permittivity: 3.73, Q value: 4545 at 6 GHz, thickness: 0.636 mm).

TABLE 2 Glass Aggregates Laminate Amount SiO₂ TiO₂ ZnO ZrO₂ BaO Relative Q value No. No. [wt %] [wt %] [wt %] [wt %] [wt %] [wt %] permittivity [at 6 GHz] Note L1 G1 90 7 2 1 — — 4.21 1360 L2 G2 90 7 2 1 — — 4.45 1279 L3 G3 90 7 2 1 — — 4.42 1714 L4 G3 100  — — — — — 4.64 1980 L5 G4 90 6.7 —   0.3 3 — 4.31 1510 L6 G4 40 48 2 2 — 8 4.02 870 Insufficient sintering L7 G5 90 7 2 1 — — 4.50 2218 L8 G6 90 7 2 1 — — 4.64 2762 L9 G7 90 7 2 1 — — 4.72 2099 L10 G7 50 32 10  — — 8 5.30 1450 L11 G8 90 7 2 1 — — 4.73 2054 L12 G9 90 7 2 1 — — 4.88 1628 L13 G10 90 7 2 1 — — 4.95 1350 L14 G11 90 7 2 1 — — 5.08 1401 L15 G12 90 7 2 1 — — 4.92 2074 L16 G13 90 7 2 1 — — 5.43 2258 L17 G14 90 7 2 1 — — 4.72 2633 L18 G15 90 7 2 1 — — 5.39 2353 L19 G16 90 7 2 1 — — 4.69 2272 L20 G17 90 7 2 1 — — 4.99 2300 L21 G18 90 7 2 1 — — 4.66 2115 L22 G19 90 7 2 1 — — 5.20 1980 L23 G20 90 7 2 1 — — 5.07 1033 L24 G21 90 7 2 1 — — 5.43 1054 L25 G22 90 7 2 1 — — 5.35 1110 L26 G23 90 7 2 1 — — 5.41 1311 L27 G24 90 7 2 1 — — 4.55 1220 L28 G25 90 7 2 1 — — 4.10 1666 L29 G26 90 7 2 1 — — 3.82 988 Insufficient sintering L30 G27 90 7 2 1 — — 3.15 3624 Insufficient sintering L31 G28 90 7 2 1 — — 4.89 836 Low Q value L32 G29 90 7 2 1 — — 3.29 855 Insufficient sintering L33 G30 90 7 2 1 — — 4.12 1194 L34 G31 — — — — — — — — Slurry gelated L35 G32 90 7 2 1 — — 4.43 1992 Insufficient sintering L36 G33 90 7 2 1 — — 4.60 2200 L37 G34 65 32 2 1 — — 4.31 1400 L38 G34 55 42 2 1 — — 4.27 1300 L39 G35 55 42 2 1 — — 4.33 1100 L40 G35 45 52 2 1 — — 4.21 1000 L41 G36 40 57 2 1 — — 4.10 600 Low Q value L42 G3 70 21 1 8 — — 4.70 1680 L43 G37 90 7 2 1 — — 4.14 1294 L44 G38 90 7 2 1 — — 4.57 1855 L45 G39 90 7 2 1 — — 4.89 1920 L46 G40 90 7 2 1 — — 5.45 1745 L47 G41 90 7 2 1 — — 3.56 912 Insufficient sintering

The results in Table 2 demonstrate that the laminates each including the glass ceramic layers each of which is a sintered article of the glass ceramic of the present invention had a low relative permittivity and a high Q value (a low dielectric loss) although they each were formed from a glass having a B₂O₃ content of 30% by weight or less. Further, the laminates suffered no issues due to dissolution or evaporation of boron.

The laminate L6 suffered sintering defects presumably because it contained less than 45% by weight of the glass G4.

The laminate L29 suffered issues such as dissolution and evaporation of boron during production presumably because it was formed from the glass G26 having a B₂O₃ content of higher than 30% by weight.

The laminate L30 suffered sintering defects presumably because it was formed from the glass G27 having a B₂O₃ content of less than 11% by weight and thus the viscosity of the glass was not sufficiently low.

The laminate L32 failed to provide a dense sintered article presumably because it was formed from the glass G29 having a weight ratio of Al₂O₃ to ZnO (Al₂O₃/ZnO) of higher than 1.64 and too much Al₂O₃ caused a high viscosity of the glass.

The laminate L47 suffered insufficient progress of sintering at 980° C. presumably because it was formed from the glass G41 having a SiO₂ content of higher than 65% by weight.

The glass G31 failed to provide a laminate because it had a weight ratio of SiO₂ to B₂O₃ (SiO₂/B₂O₃) of lower than 1.21 and thus the ceramic slurry was gelated by heating at 980° C.

The laminate L35 suffered issues such as dissolution and evaporation of boron during production presumably because it was formed from the glass G32 having a weight ratio of SiO₂ to B₂O₃ (SiO₂/B₂O₃) of lower than 1.21.

The laminate L31 suffered neither insufficient sintering nor gelation of the ceramic slurry, but had a Q value of lower than 1000, i.e., had a high dielectric loss. This low Q value is presumably derived from the fact that the laminate L31 was formed from the glass G28 having a weight ratio of Al₂O₃ to ZnO (Al₂O₃/ZnO) of lower than 0.75.

The laminate L41 suffered neither insufficient sintering nor gelation of the ceramic slurry, but had a Q value of lower than 1000, i.e., had a high dielectric loss. This low Q value is presumably derived from the fact that the laminate L41 contained less than 45% by weight of the glass G36.

REFERENCE SIGNS LIST

-   -   1: laminate     -   2: electronic component     -   3: glass ceramic layer     -   9, 10, 11: conductive layer     -   12: via hole conductive layer     -   13, 14: chip component     -   21: multilayer green sheet     -   22: green sheet 

1. A glass comprising: SiO₂ at a content of 15% by weight to 65% by weight; B₂O₃ at a content of 11% by weight to 30% by weight; Al₂O₃; and ZnO, wherein a weight ratio of the SiO₂ to the B₂O₃ (SiO₂/B₂O₃) is 1.21 or higher, a weight ratio of the Al₂O₃ to the ZnO (Al₂O₃/ZnO) is 0.75 to 1.64, and wherein an alkaline-earth metal is excluded as a material contained in the glass.
 2. The glass according to claim 1, wherein the content of the SiO₂ is 55% by weight to 65% by weight.
 3. The glass according to claim 1, wherein the content of the B₂O₃ is 18.8% by weight to 30% by weight.
 4. The glass according to claim 1, wherein Li is excluded as a sub-component.
 5. The glass according to claim 1, wherein the weight ratio of the SiO₂ to the B₂O₃ (SiO₂/B₂O₃) is 5.91 to 1.21.
 6. The glass according to claim 1, further comprising Li as a sub-component.
 7. The glass according to claim 6, wherein the glass has a Li₂O content of 0.05% by weight to 1% by weight.
 8. The glass according to claim 7, wherein a sum of an amount of the sub-component is 0.05% by weight to 5% by weight of the weight of a whole of the glass.
 9. The glass according to claim 1, further comprising at least one metal as a sub-component, the at least one metal being selected from the group consisting of an alkali metal and a different metal from that of a main component of the glass.
 10. The glass according to claim 9, wherein the alkali metal comprises at least one selected from the group consisting of Na and K, and the different metal comprises at least one selected from the group consisting of Ti, Zr, and Sn.
 11. The glass according to claim 8, wherein a sum of an amount of the sub-component is 0.05% by weight to 5% by weight of the weight of a whole of the glass.
 12. A glass ceramic comprising 45% by weight to 100% by weight of the glass according to claim
 1. 13. The glass ceramic according to claim 12, further comprising an aggregate.
 14. The glass ceramic according to claim 13, wherein the aggregate comprises at least one compound selected from the group consisting of SiO₂, TiO₂, ZnO₂, ZrO₂, Al₂O₃, and BaO.
 15. A glass ceramic comprising 65% by weight to 100% by weight of the glass according to claim
 1. 16. A multilayer ceramic electronic component comprising multiple glass ceramic layers each of which is a sintered article of the glass ceramic according to claim
 12. 